Samples / Task 1 Academic report / Process diagram / Band 7.5

Municipal Water Treatment Process Academic Report

A Band 7 model answer describing the process of producing drinking water at a municipal treatment plant, featuring realistic candidate errors.

The question

The diagram below shows how drinking water is produced at a municipal treatment plant. Summarise the information by selecting and reporting the main features, and make comparisons where relevant. Write at least 150 words.

Producing drinking water at a municipal treatment plant. Figures are given in the caption below. — Producing drinking water at a municipal treatment plant
Stages in order: Reservoir -> Coarse screen -> Mixing tank, coagulant added -> Flocculation basin -> Sedimentation tank, sludge removed -> Sand filters -> Chlorine contact tank -> Covered storage, then distribution

The diagram illustrate the multi-stage process of how clean drinking water is produced at a municipal treatment plant. Overall, it is clear that the water undergoes a series of physical and chemical treatments, starting from a natural reservoir and ending with covered storage before distribution. The entire system can be divided into filtration, chemical treatment, and final disinfection stages. On the first stage of the process, raw water is piped from a reservoir through a coarse screen to remove large debris. After the water is screened, it is pumped into a mixing tank where coagulant chemical are added to help suspended particles clump together. Next, the water flows into a floculation basin to allow these clumps to grow larger. Following this, the water enters a sedimentation tank, where heavy particles settle to the bottom and is removed as sludge. In the subsequent stages, the partially clarified water is passed through sand filters to eliminate any remaining fine impurities. Once filtered, the water is directed to a chlorine contact tank for disinfection, which kills harmful bacteria. Finally, the safe drinking water is kept in a covered storage tank until it is distributed to the community.

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This answer was written by a language model to a real exam question, then scored by Bandly against the four public band descriptors. The band is a software estimate. No examiner has marked it, and the band a real examiner would award may differ. Scored with google/gemini-3.5-flash on 2026-09-08.

Estimated overall

7.5

Mean of the four criteria, rounded the way the exam rounds it.

Task Achievement 9

You achieve Band 9 for Task Achievement because you fully cover all stages of the process and provide a clear, well‑developed overall description.

Coherence and Cohesion 7

Your response demonstrates clear progression and logical organisation of ideas, but there is some under-use of cohesive devices, particularly in varying the sentence beginnings.

Lexical Resource 6

Your response uses an adequate range of vocabulary for the task, but there are some inaccuracies in word choice and word formation that prevent a higher score.

Grammatical Range and Accuracy 7

While the response demonstrates a good control of grammar and punctuation, occasional errors in verb agreement and article usage prevent a higher score.

What would take this higher

To improve your score, you should focus on your weakest criterion, Lexical Resource, by eliminating minor spelling and word formation errors. For instance, correcting the spelling of "floculation" to "flocculation" and changing the singular "coagulant chemical" to the plural "coagulant chemicals" would immediately elevate the precision of your vocabulary. Additionally, refining collocations such as changing "On the first stage" to "In the first stage" will help you demonstrate the natural word choices required for a higher band.

Find out what this essay would score

Paste your own answer and Bandly returns an estimated band for each of the four criteria, with the sentences that pulled the score down. Under a cent an essay, about six seconds.

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